In April, we 
announced that 
Search Network with Display Select support would begin in AdWords API v201402. Now that all previous API versions have been sunset, we’re on schedule to begin migrating all 
Search and Display Network campaigns to 
Search Network with Display Select beginning 
September 16, 2014.
This blog post will walk through everything you need to know about setting up your campaigns, including what this migration means for your campaign-creation code. You can proactively migrate your campaigns by setting their 
displaySelect property to  
true.
Remember, this will 
not affect Search-only or Display-only campaigns. Only campaigns that target both networks simultaneously will be migrated.
If you have any questions about this change, please contact us on the 
forum or via our 
Google+ page.
 - Michael Cloonan, AdWords API Team.
 - Michael Cloonan, AdWords API Team.